The Electronics

So, now for the electronics element of this project.

Control Board

There are many 3D printer control boards out there. I wanted to go with one that has a good ecosystem and has good support. For this reason, I decided to go with the RAMPS 1.4. It is limited in it's processing power, but it is well established, and has wide support, not to mention a number of firmwares that can be used.

The RAMPS series of controllers are usually one part of a two part system. The main processing element of the setup is an Arduino Mega 2560. This board is responsible for receiving and processing the gcode and then calculating how the printer will move to match what has been requested. There are some custom RAMPS boards out there that incorporate the Arduino on one board. I decided to stay away from these due to the fact that if the 3D printer didn't work out, I could use the Arduino for another project.

The RAMPS board allows the Arduino, with the addition of a suitable power supply, to interface with the stepper motors, sensors and heating elements, of which will draw more power than the Arduino can supply.

Although  I would recommend purchasing an official Arduino and RAMPS boards (I already have an official Ardunio Uno),  I opted to order up a version from a well know Chinese supplier. This was mainly due to the fact that I had to keep the costs down. As a result of this choice, I was expecting to have to deal with some quality issues later on down the line.

As part of my order, I also decided to include a full graphics module. This seemed better that the 2x16 screen and also gave me the ability to print directly from an SD card.this seems a small point but it is worth noting if your PC crashes for any reason that 5hr print has just been ruined.

So after a few weeks my order arrived. Surprisingly it came in a nice plastic box and in sealed anti-static bags. It came with "almost" everything I needed to wire up and get going (We'll get onto the "almost" later). 

The package included: -

• 1 x Arduino clone
• 1 x RAMPS clone 
• 5 x DRV8825 stepper driver (1 for each axis and enough for 2 extruders)
• 5 x Heat syncs for stepper drivers
• 1 x Full graphic display
• 1 x Adapter to connect display to RAMPS
• 1 x USB cable

On first inspection, the quality seem very good. But while I was attempting to connect the RAMPS board to the Arduino, I found that there were issues lining up all of the pins. It later transpired that the headers on the Arduino were leaning slightly and this was obvious that this was done during manufacture. The cautious application of force in a strategic area sorted the issues and all went well from there.

As I said earlier, the deliver came with "almost" everything that I needed. For some reason the supplier decided not to provide me with the required jumpers that allow the RAMPS to do micro stepping. In short, microstepping allows the motor that drives the printer to be controlled with a greater level of accuracy. Thankfully my hording of old computer equipment provided me with a bounty of redundant jumpers from old motherboards and hard drives.

Now it was time to prepare the DRV8825 stepper drivers to be installed. This was relatively easy, but care still needed to be taken due to very tight tolerances between the top of the driving chip ad the back of the headers. To install the heatsync, it was a simple case of removing the thermal tape paper, aligning the heatsync with the chip and pressing down, while at the same time making sure the heatsync was not touching any other parts. 

Nnext up, the driver boards need to be inserted into the RAMPS board. Again, this was relatively easy, but care needed to be taken to orient the boards correctly. If these are plugged in backwards they fry the driver chip, so it's best not to get this part wrong. to install them, the small trim pot needs to be furthest away from the cower connectors. the picture below shows the green power connector on the left and the small round trim pots on the right hand side of each driver board.

At this point I decided to take a rest from all of the concentration. Unfortunately for you, this is where my lack of blogging skills showed, as I neglected to take pictures through the next phase.

I'll do my very best to recreate the process to complete the build, but i was having WAY too much fun at this point :)

Until next time

Build Update - The Printer Structure

Ok.. ok.. so looking though my photos of the build so far, I noticed one of two terrible things had happened: -

1. I had some how not uploaded pictures of the assembly process from my phone before it died
2. I had forgotten to take pictures of the build process.

I was sure No.2 was not an option, but it has been a while since this was completed, so I cannot be 100% sure. So i'm putting this down to Newbie Mistake No.1 - "Not taking enough pictures during the process!".

In spite of this I will attempt to recant the process and submit new pictures to fill in the gaps.

So the time has come to put all of this together, and hopefully get a printer at the end of it.

First I needed to cut out the printer bed. This is where all of the printing will take place and needs to be as accurate as I can make it. Thankfully I had some 12mm plywood left over from some DIY work in the house that could be re-purposed for this. I downloaded a drawing of the base which had all of the measurements.

I then printed this out on paper at a 1-to-1 scale and measured it for accuracy. Once I was happy, I stuck it to the ply and proceeded to cut it out with a jigsaw.

Once cut out, I drilled the 6 holes out with a 4mm bit on my drill press where the motor mounts would be fitted. I then took a similar sized board and screwed it to the cutout though 3 of the holes I just drilled. I then setup a router table with a straight cutting bit with a bearing. Using the first cutout as a template, I used the router to cut out the top. I then drilled out the 3 of the holes, moved the screws one by one, and drilled the remaining 3, again using the first cut as a template to ensure they were both exactly the same. 

For the very bottom, I decided to trace around the bed and extend by 25mm all the way around and extend at the front. this gave the motor mounts and the LCD something to sit on.

Now all of the wood cutting had been completed it was time for assebly. One by one, I fixed each of the 3 the NEMA17 motors to the motor mounts with 4 10mm M3 hex screw and washers. I then inserted each of the 6 8mm smooth rods into the motor mount and tightened with 6 15mm M3 hex screw, a washer and nut. Each of the 3 assemblies were then screwed through the base giving the first signs of the size and scale of the printer.  

I then assembled the 3 idler brackets with a bearing that would hold the timing belts that would run the printer. This was done using an M8 hex screw and nylock nut. These were then attached at the other end of the M8 smooth rod at the top of the printer and tightend with 4 15mm M3 hex screws, a washer and nut. 

Things had come together quickly to this point so I decided to get an imopression of the final size . I attached the GT2 drive pulley to the NEMA17 motor shafts and placed the top on the printer. I knew the top and idlers would have to come back off to attach the end effector assemble, but I wanted to get a feel for the final look.

So far so good, but I knew the next step would be challenging. Getting the electronics installed and working.

Minor update

Well, needless to say I have been a little preoccupied since my last post.
Alot has happened and I have not had very much time to post about progress.

Currently the printer is running, and I have had some good practice printing in PLA and ABS materials.

I have however, run into some stumbling blocks that could be down to my my poor fabrication skills, or due to my lack of research (something i will go into in more detail in future posts.)

for now I leave you with a montage of images of work I have done in over the last month or so.

"First Drawing"

"A little bit more accuracy"

"Extruder designed in OpenSCAD and printed on ply wood"

"Roughly cut out :s "

"Hot End holder traced on Ply and Cut"

"Waiting to be drilled and cut to take the hot end"

"Extruder Assembled.... sort of"

"It Works.... First Print"

"Quick... Print some replacements before it all falls apart!"

"Thats Better!"

"First Stress test. Skull next to my Fitbit for scale"

"Not Bad for a first go"

"First fix. broke a pulley in my food mixer (left) OpenSCAD replacement (right). And best of all. it works :D"

"Larger Skull (5hr Print time"

Replacement rod ends in ABS

"Ginger bread house cookie cutters. much fun was had with the kids :)"

"Decided to be lazy and print these so I don't have to tie my shoes :)" 

Until next time........